Respect string type when parsing validation rules' examples

[joligoms]

This PR implements @Tryfciu 's code that fixes the problem mentioned here.

Now, when we have an @example doc specification with a numeric value, it treats this value according to the type specified for it right at the body request example. So, if this numeric value is a string, it will have quotation marks and won't be parsed into a number.

Here's a practical example:

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array<string, \Illuminate\Contracts\Validation\ValidationRule|array<mixed>|string>
     */
    public function rules(): array
    {
        return [
            // @example decade00-0000-4000-a000-000000000000
            'id' => 'uuid|required',
            // @example 700100201
            'phone_number' => 'string|digits:9',
            // @example +1
            'some_value' => 'string',
        ];
    }

Notice that phone_number and some_value both have numeric values but should be treated as strings because of the validation type.

So instead of being parsed right into numbers, they will be actual strings:

This also fixes the fact that if we have a string like "+1", it won't be parsed into just 1 like before :)

Now of course, if we specify that they are numbers, it treats them as so:

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array<string, \Illuminate\Contracts\Validation\ValidationRule|array<mixed>|string>
     */
    public function rules(): array
    {
        return [
            // @example decade00-0000-4000-a000-000000000000
            'id' => 'uuid|required',
            // @example 700100201
            'phone_number' => 'integer|digits:9',
            // @example +1
            'some_value' => 'integer',
        ];
    }